钛基复合材料的进展

综述了各种钛基复合材料的制备工艺、机械性能及其应用;展望了钛基复合材料的发展前景,建议大力开展对钛基复合材料的研究。     

TiC颗粒增强钛基复合材料的摩擦磨损性能

采用Ti粉末分别与碳化物Mo2C和VC粉末混合,通过冷等静压、真空高温烧结原位生成6种不同成分的TiC颗粒增强钦基复合材料,用UMT-3型摩擦试验机研究合金元素Mo和V以及Mo2C、VC添加量对钛基复合材料干磨擦性能的影响.测定不同样品的洛氏硬度和基体的显微硬度,用金相显微镜(OM)、X射线衍射仪(XRD)观察和分析样...     

钛基复合材料板材轧制研究进展

钛基复合材料中的增强相极大增加了其热加工难度,导致大变形或大尺寸高性能钛基复合材料板材的制备困难。从钛基复合材料板材发展现状出发,围绕其热轧制技术,分析了轧制温度、变形量及轧后热处理工艺对板材微观组织演变和力学性能的影响规律,重点分析了轧制过程和热处理过程增强相与基体组织之间的相互作用。最后指出当前钛基复合材料板材轧制研究存在的不足及未来的发展趋势。     

粗颗粒氧化铝陶瓷基复合材料在不同载荷下的耐磨性研究

本文研究了粗颗粒氧化铝陶瓷基复合材料在无润滑条件下不同载荷时的耐磨性能 ,并对其磨损机理进行了探讨。试验结果表明 ,该材料对外加载荷具有较大的敏感性。通过对磨痕形貌的观察研究 ,认为该材料的磨损机理是以脆性剥落和磨粒磨损为主 ,并同时伴随一定程度的疲劳磨损     

自生颗粒增强钛基复合材料的研究进展

从钛合金基体和增选择ＴＭＣｓ的制备方法,ＴＭＣｓ的微观组织和界面结构,ＴＭＣｓ的性能和ＴＭＣｓ的应用５ 个不同方面叙述了自生颗粒增强型钛基复合材料的研究进展。．     

TiNi形状记忆合金强化的钛基和铝基复合材料

机敏材料在受外部刺激时可作出相应反应 ,以补偿相应的变化或增强预想的效果。连续 Ti Ni SMA纤维增强剂可以改进材料高温下的屈服应力和断裂韧性 ,同时具有机敏材料的特性 ,属于机敏材料。用 SMA作增强剂强化机敏材料的原理是 ,埋入基体中的 SMA室温加载后由奥氏体向马氏体转变 ,加热后又发生逆转变。逆转变相变过程中 ,复合材料里的 SMA收缩 ,在 SMA内产生拉应力 ,基体内产生压应力。基体中的压应力是提高机敏材料拉伸性能的主要因素。1　复合材料的制备使用四种方法制造 SMA增强复合材料 :真空热压 ,热挤压 ,火花等离子烧结和包…     

原位自生钛基复合材料的研究进展

原位自生钛基复合材料以其高比强度和高比模量引起了人们的广泛关注,尤其是如何提高其高温性能成为近年来钛基复合材料研究的热点.该文详细综述了原位自生钛基复合材料的各种制备方法、增强体与钛基体的选择、各种增强体的反应体系以及原位自生钛基复合材料的组织结构与力学性能,指出了原位自生钛基复合材料今后的发展方向.     

激光熔覆速率对熔覆层显微组织及耐磨性的影响研究

分别采用高速和常规的熔覆速率,进行了高硼不锈钢合金粉末的激光熔覆试验.试验结果表明,相同功率条件下,熔覆速率对组织的影响较大.熔覆速率越快,枝晶尺寸越细小.高速激光熔覆下,熔覆层晶粒尺寸可达1～2μm,且组织更均匀.高速激光熔覆制备的熔覆层中奥氏体含量偏高,从而熔覆层的耐磨性能有所下降.     

粉末冶金原位合成法制备钛基复合材料的研究进展

本文从制备钛基复合材料所需的基体和增强体的选材出发,阐述了粉末冶金方法在颗粒增强钛基复合材料中的研究与应用,并就未来粉末冶金技术在颗粒增强钛基复合材料中的研究方向阐明了观点。     

SiC纤维增强钛基复合材料研究进展

概述了作者研究组近年来在SiC纤维增强钛基复合材料研究领域开展的工作及取得的进展.采用具有自主知识产权的SiC纤维,研究了PVD先驱丝制备方法和真空热压/热等静压复合材料成形工艺,获得700℃拉伸强度＞1500MPa的SiCf/Ti-6A1-4V复合材料,分别制备出长度＞400mm和直径＞200mm的钛基复合材料棒材和环形件.此外,分别采用粉末布与粉浆涂挂先驱丝两种低成本方法制备出钛基复合材料,确定了新的胶粘剂并优化了相关工艺参数.     

SiC颗粒增强铝基复合材料的研究进展

简要介绍了SiC颗粒增强铝基复合材料的优点及几种制备方法,包括搅拌法、浸渗法、喷射法、粉末冶金法和固液分离法;并对其后热变形加工参数对复合材料的性能影响进行了论述;最后,展望了粉末冶金法制备铝基复合材料的发展前景。     

非连续相混杂增强金属基复合材料的研究进展

论述了非连续增强金属基复合材料的研究概况,简要介绍了非连续相混杂增强金属基复合材料常用的几种制备方法,包括搅拌熔铸法、压力铸造法、无压浸渗法、喷射沉积法、粉末冶金法、原位反应法等,同时对常见的3种增强体的混杂类型:颗粒+颗粒、短纤维+晶须(短纤维)、颗粒+晶须(短纤维)增强金属基复合材料的性能和国内外研究现状进行了综述,指出了非连续相混杂增强金属基复合材料存在的问题,并对其今后的发展进行了展望。     

石墨烯增强铝基复合材料制备技术研究进展

石墨烯具有独特的结构特点和优异的物理化学性能,是理想的复合材料增强体。本文综述了石墨烯增强铝基复合材料制备方法的现状,着重介绍了石墨烯的分散工艺和复合材料的成型方法,讨论了这些方法对复合材料性能的影响,并从混粉和烧结工艺方面提出了石墨烯增强铝基复合材料制备方法的发展方向。     

Fatigue in selectively fiber-reinforced titanium matrix composites

Many applications of the Ti alloy matrix composites (TMCs) reinforced with SiC fibers are expected to use the selective reinforcement concept in order to optimize the processing and increase the cost-effectiveness. In this work, unnotched fatigue behavior of a Ti-6Al-4V matrix selectively reinforced with SCS-6 SiC fibers has been examined. Experiments have been conducted on two different model panels. Results show that the fatigue life of the selectively reinforced composites is far inferior to that of the all-TMC panel. The fatigue life decreases with the decreasing effective fiber volume fraction. Suppression of multiple matrix cracking in the selectively reinforced panels was identified as the reason for their lack of fatigue resistance. Fatigue endurance limit as a function of the clad thickness was calculated using the modified Smith-Watson-Topper (SWT) parameter and the effective fiber volume fraction approach. The regime over which multiple matrix cracking occurs is identified using the bridging fiber fracture criterion. A fatigue failure map for the selectively reinforced TMCs is constructed on the basis of the observed damage mechanisms. Possible applications of such maps are discussed.     

SiC/C-Cu复合材料的载流磨损性能

采用粉末冶金法制备SiC/C-Cu复合材料,研究SiC颗粒含量对该材料组织结构与物理性能的影响,并在HST-100载流摩擦磨损试验机上进行载流磨损试验,研究摩擦速度、电流密度与SiC颗粒含量对SiC/C-Cu复合材料磨损率的影响以及磨损机理的变化。结果表明:SiC颗粒均匀分布于铜基体中。随SiC含量增加,复合材料的硬度和孔隙率都逐渐增大,密度和导电率降低。添加SiC颗粒可增强C-Cu复合材料的抗磨损性能,材料的磨损率随摩擦速度和电流密度增加而增加,随SiC含量增加呈先降低后上升的趋势,含2%SiC(质量分数)的SiC/C-Cu复合材料具有优异的抗载流磨损性能。添加SiC颗粒可减少摩擦磨损过程中铜基体的粘着磨损,磨损机理主要为磨粒磨损和电弧侵蚀磨损。     

High-temperature wear and deformation processes in metal matrix composites

Dry-sliding wear behaviors of a particulate-reinforced aluminum matrix composite 6061 Al-20 pet A1₂O₃ and an unreinforced 6061 Al alloy were investigated in the temperature range 25 °C to 500 °C against a SAE 52100 bearing steel counterface. Experiments were carried out at a constant sliding speed of 0.2 m·s^- at different test loads. The deformation behavior of the materials was studied by performing uniaxial compression tests in the same temperature range as the wear tests. Both alloys showed a mild-to-severe wear transition above a certain test temperature. In the mild wear regime, the wear rate and the coefficient of friction of the unreinforced 6061 Al decreased slightly with temperature, but the temperature had almost no effect on the wear rate and the coefficient of friction of the 6061 Al-20 pet Al₂O₃ in the same regime. Particulate reinforcement led to an increase in the transition temperature and a 50 to 70 pet improvement in the wear resistance in the severe wear regime. This was attributed to the formation of tribological layers consisting of comminuted A1₂O₃ particles at the contact surface. High-temperature compression tests showed that the flow strength of 6061 Al-20 pet A1₂O₃ and 6061 Al decreased monotonically with temperature and both alloys exhibited a work-softening behavior at temperatures higher than the inflection point on the flow stressvs temperature curves. The logarithmic maximum stressvs reciprocal temperature relationship was not linear, indicating that the deformation processes were too complicated to be characterized by a single activation energy over the whole temperature range. For the range of 250 °C to 450 °C, the activation energy for deformation was estimated to be 311 kJ·mol^-1; for both the matrix alloy and the composite. Severe wear proceeded by thermally activated deformation processes involving dynamic recrystallization along a subsurface strain gradient. A power-Arrhenius type relationship was found to describe well the observed dependence of severe wear rates on the applied load and temperature. This relationship was used to calculate an apparent activation energy for wear of 87 kJ·mol^-1 for the particulate-reinforced composite and 33 kJ·mol^-1 for the matrix alloy. The wear regimes at elevated temperatures are represented in a deformation mechanism map and the relationship between high-strain deformation processes and severe wear are discussed.     

Elastic shielding during fatigue-crack growth of titanium matrix composites

The role of elastic shielding in reducing the local stress intensity factor (SIF) range during fatigue crack growth (FCG) has been investigated using several single-ply composites with significantly different interfacial characteristics. The specimen geometry necessitated the fatigue crack to initially grow through a monolithic matrix region before impinging on a set of longitudinally oriented fibers. This facilitated the assessment of the crack shielding phenomenon from two regions: the region where the crack interacted with the first fiber, and at high stress levels when nonbridging conditions prevailed in the fibrous region. The extent of shielding was nearly identical in the two measurements for a given composite system. However, the shielding contribution was found to depend on the interface bond strength; the interface with the highest bond strength provided the largest degree of crack retardation in both cases. A preliminary assessment of this dependency has been provided. The implications of using the correct shielding factor on both fiber strength and life prediction are also discussed. This article is based on a presentation made in the symposium “Fatigue and Creep of Composite Materials” presented at the TMS Fall Meeting in Indianapolis, Indiana, September 14–18, 1997, under the auspices of the TMS/ASM Composite Materials Committee.     

高温钛合金和颗粒增强钛基复合材料的研究和发展

简要回顾了高温钛合金的研究和发展历程,指出现代高温钛合金进一步发展需要解决的主要难题.综述了颗粒增强钛基复合材料的研究现状,从基体的选择、增强相的选择和制备工艺等3个方面,较详细地阐述了颗粒增强钛基复合材料设计中的基本任务.最后对今后的发展趋势进行了展望.     

Fracture resistance of fiber-reinforced ceramic matrix composites

The influence of the properties of the fibers, the matrix and the interface on the mechanical properties of fiber reinforced ceramics is analyzed by a simplified method previously developed by the authors for cohesive materials. The method parts from the assumption that crack displacements are known a priori and furnishes, in a simple and easy way, the fracture resistance curves versus crack length. The numerical results from the model are compared with experimental data from the literature. Finally, the model is used to assess the influence of fiber strength, interface slipping shear stress, fiber radius and fiber defect distribution on the fracture resistance and ductility of fiber-reinforced ceramic composites.     

用于制备高性能钛基复合材料的碳包覆钛复合粉体研究进展

钛基复合材料中增强相的形貌和分布是决定材料性能的关键,常规粉体机械混合后烧结引入增强相的方式存在形貌难调控、分布单一且均匀性差等问题,导致其强化效果不佳。针对该问题,本团队开发了一系列碳包覆钛复合粉体,通过设计包覆碳源的结构与组成调控粉体烧结过程中增强相的形成路径,不仅实现了增强相形貌调控和不同形貌的组合搭配,而且得到了晶内和晶界双增强相组织,大幅提升了钛基复合材料的力学性能。在此基础上,将碳包覆钛复合粉体拓展应用至钛基复合材料的3D打印领域,解决了高品质复合粉体缺乏并制约其发展的瓶颈问题。总结并评述了碳包覆钛复合粉体在制备钛基复合材料中取得的研究结果与工作进展,为增强相设计与调控提供新的研究思路及技术路线。